Simple, the best Halo yet (or ever I guess.)
But for the short 7 hours it took to play Reach's campaign on normal I had a blast. The bit longer to do it on Heroic and Legendary, even better. The weapons are all well balanced, no head shots across the map with pistols etc. (well rarely.) The mobs were very well done, both graphically and their AI. No, not perfect, I mean come on, the campaign is just a 10 hours tutorial for on-line right? The one thing I was really surprised at was there is a fairly good plot line this time around. I know, many could careless, but it did make the campaign worth the time. (Yes, I'm getting old.)
I have had little time so far for multiplayer, but the little I have played was intense. No lag issues to speak of. Games came off without a hitch. No weird drops etc.
Lastly I did dabble with the VERY easy to learn/use Forge World. I am impressed with is capabilities and how fast I had a decent map up for playing on. With a little work even the non-designer types can have amazing (well, very good) maps up in a snap.